title: Response of immortalized murine cementoblast cells to hypoxia in vitro.
abstract: OBJECTIVE
  The aim of the study was to investigate the impact of hypoxia on proliferation, apoptosis and mineralization of cementoblast-like cells (OCCM-30) in vitro.
  
  
  METHODS
  The effects of different periods of hypoxia (2% O2) on proliferation, apoptosis, cementoblastic potential and root cementum resorption capability of OCCM-30 were evaluated, by using MTT, flow cytometry, alkaline phosphatase (ALP) activity assay, reverse transcription-polymerase chain reaction measurement, enzyme-linked immunosorbent assay and mineralization nodule formation assay.
  
  
  RESULTS
  OCCM-30 viability was significantly inhibited by hypoxia while the apoptosis ratio was enhanced in a time-dependent manner; hypoxia inducible factor-1α and vascular endothelial growth factor mRNA were induced by hypoxia in different manners; temporary hypoxia (<24 h) stimulated cementoblastic function of OCCM-30, while long-term hypoxia inhibited it, manifested by decreased mRNA level or release of ALP, osteocalcin, bone sialoprotein, osteopontin and osteoprotegerin. In addition, hypoxia affected mineralized nodule formation of OCCM-30 in a time-dependent fashion; moreover, root cementum resorption function was also induced by hypoxia, manifested by increased receptor activator of nuclear factor kappa B ligand mRNA and protein expression.
  
  
  CONCLUSIONS
  Temporary exposure of OCCM-30 to hypoxia inhibited proliferation, promoted apoptosis and mineralization, while longer duration of hypoxia could inhibit the cementoblast function. The findings may provide theoretical basis for developing novel therapeutics to prevent root resorption during orthodontic treatment.
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China.
authors.forename: Yeke
authors.initials: Y
authors.lastname: Wu
authors.forename: Xianglong
authors.initials: X
authors.lastname: Han
authors.forename: Yongwen
authors.initials: Y
authors.lastname: Guo
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Ren
authors.forename: Jingyu
authors.initials: J
authors.lastname: Li
authors.forename: Dongqing
authors.initials: D
authors.lastname: Ai
authors.forename: Lufei
authors.initials: L
authors.lastname: Wang
authors.forename: Ding
authors.initials: D
authors.lastname: Bai
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003739:Dental Cementum / Q000166:cytology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D000860:Hypoxia / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D058574:Integrin-Binding Sialoprotein / Q000378:metabolism; D051379:Mice; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D058574:Integrin-Binding Sialoprotein; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D000469:Alkaline Phosphatase
keywords: BSP; Cementoblast function; Cementoblast-like cell; DSP; HIF-1α; Hypoxia; Mineralization; OCN; OPG; OPN; Osteoprotegerin; PDL; RANK; RANK ligand; RANKL; VEGF; bone sialoprotein; dentin sialoprotein; hypoxia-inducible factor-1α; osteocalcin; osteopontin; periodontal ligament; receptor activator of nuclear factor-kappaB; vascular endothelial growth factor